J. Aquaculture Vol. 21(1), 26-33, 2008 한국양식학회지 Journal of Aquaculture Korean Aquaculture Society 사료내맥반석과 BAISM 복합첨가가치어기뱀장어 Anguilla japonica 의성장과내병성에미치는영향 배준영, 한경민, 이준호, 김상은 1, 이정열 2, 배승철 * 부경대학교양식학과 / 사료영양연구소, 1 ( 주 ) 다비스톤, 2 군산대학교해양생명과학부 Effects of Dietary Quartz Porphyry and Feed Stimulants, BAISM Supplementation on Growth Performance and Disease Resistance of juvenile eel Anguilla japonica Jun-Young Bae, Kyungmin Han, Jun-Ho Lee, Sang-Eun Kim 1, Jeong-Yeol Lee 2 and Sungchul C. Bai* Department of Aquaculture/Feeds & Foods Nutrition Research Center, Pukyong National University, Busan 708-737, Korea 1 Davistone Co. Ltd., Busan 607-822, Korea 2 School of Marine Life Science, Kunsan National University, Gunsan 573-701, Korea This study investigated the synergistic effects of dietary supplementation of quartz porphyry (QP) and a laboratory developed feed stimulants, BAISM (BS) on growth performance and utilization as the additives for juvenile eel Anguilla japonica. Six isoenergetic experimental diets (18.2 kj/g) were formulated to contain 50% crude protein, 15% lipid with or without dietary QP (Song-Gang stone, Davistone, Korea) and BS supplementation. QP and BS were provided at 0% in the control diet (Q 0B 0) and at 0.7% QP+0% BS (Q 0.7B 0), 0.7% QP+0.3% BS (Q 0.7B 0.3), 0.7% QP+0.5% BS (Q 0.7B 0.5), 0.7% QP+0.75% BS (Q 0.7B 0.75) and 0.7% QP+1.0% BS (Q 0.7B 1.0) in experimental diets on dry matter basis. After four weeks of adaptation, triplicate groups of 30 fish initially averaging 15±0.1g (mean±sd) were randomly distributed into each aquarium, and they were fed one of the experimental diets for 8 weeks. By the end of the feeding trial, weight gain (%), specific growth rate (%), feed efficiency (%) and protein efficiency ratio of fish fed diet Q 0.7B 0.5, Q 0.7B 0.75 and Q 0.7B 1.0 were significantly higher (P<0.05) than those of fish fed the other diets. But, Q 0.7B 0.5, Q 0.7B 0.75 and Q 0.7B 1.0 were no significant differences (P<0.05). In challenge test, fish were infected by intraperitoneal injection of 0.1 ml bacterial suspension with Edwardsiella tarda per fish after the feeding trial. As a result, fish fed QP and BS supplemented diets have a significantly higher cumulative survival rate than those of fish fed control diet (P<0.05). In conclusion, these results indicated that the optimum dietary supplementation level of QP and BS could be approximately 0.7% quartz porphyry+0.5% BAISM (Q 0.7B 0.5) of diet based on WG, FER, SGR, PER, cumulative survival rate in juvenile eel A. japonica. Keywords: Anguilla japonica, Eel, Edwardsiella tarda, Quartz porphyry, Stimulants, BAISM 서론 Anguilla japonica는국내에서상업적으로중요한내수면양식어종으로고밀도양식에의한연간생산량은 7,966 톤에달하고, 내수면양식어류생산량인 15,879톤의절반이상 (50.4%) 을차지하고있다 (MOMAF, 2006). 이러한뱀장어고밀도양식은효율을높일수는있으나, 인위적인양식시스템에서뱀장어는다양한스트레스 ( 고밀도사육, 물리적장애, 수질악화, 항생제및화학약품의남용, 선별등 ) 에노출되고있다 (Wendelaar *Corresponding author: scbai@pknu.ac.kr Bonga, 1977). 이러한양식환경은사육중인뱀장어의체내에너지대사의불균형으로인한성장및면역력저하 (Barton and Iwama, 1991) 를유발하여생산량의감소를야기하는직접적인원인으로알려져있다 (Pickering, 1992). 또한, 양식장시설내서식하고있는상재세균이생산량감소의주요한요인으로지적되고있다 (Vadstein, 1997). 세균성질병으로인한문제점을해결하기위해사육수를소독하거나항생제를사용하기도하는데, 이러한방법들은세균개체군간의균형을불안정하게만들어근시안적인해결책에지나지않는다. 장기간의항생제사용은어류에게많은스트레스를줄뿐만아니라환경오염및인체에도악영향을미칠수있다 (Park, 2004). 특히, 상품으로시 26
뱀장어사료내맥반석과 BAISM 혼합첨가효과 27 판시항생제잔류검사시행으로인해항생제및약제의오남용에대해심사숙고해야할시점에있다 (Han, 2003). 따라서최근화학제제가아닌친환경적인양어사료첨가제에대한관심이집중되고있고, 양식어류의성장과내병성을향상시킴과동시에사료유실을최소화하기위한첨가제의필요성이대두되고있다. 현재까지양어용사료첨가제에있어서산가수분해물질 (Choi et al., 2002), 아미노산혼합물 (Kim et al., 2002a), Chlorella (Kim et al., 2002b), β-1,3 glucan (Han, 2003), 어보산 (Kim et al., 1998) 등에관한연구가해산어를중심으로수행된바있으나, 뱀장어에관한연구는거의없다. 본연구에서연구에서이용된맥반석 (quartz porphyry) 은화성암중석영암반에속하는암석으로 SiO 2 과 Al 2CO 3 및 40여종의미네랄로구성되어있다. 그주요한특성으로표면과내부의무수한미세구멍이모세관현상을일으켜유해물질들을흡착, 분해및제거하는효과가있는것으로보고된바있고 (Yoo, 2003), 치어기넙치에서첨가제로써이용가능성을확인한바있다 (Choi et al., 2004). 또한, BAISM은아미노산핵산관련화합물질로넙치 (Choi et al., 2002; Han, 2003; Yoo et al., 2007) 와조피볼락 (Kim et al., 2002a) 에서섭취촉진물질로효과가있음이보고되었다. 본연구는뱀장어의성장과내병성을향상시킴과동시에사료유실을최소화할수있을것으로판단되는맥반석과 BAISM 의사료내혼합첨가가치어기뱀장어의성장과체성분에미치는영향과질병저항성을확인하고, 사료내적정첨가농도를구명하였다. 재료및방법실험어및사육관리실험어는전라남도나주에소재한양만장으로부터구입한치어기뱀장어를부경대학교수산과학대학내실험실로운반하여 500 L FRP 수조에서실험환경에적응할수있도록 4주간예비사육후, 평균어체중 15±0.3 g (mean±sd) 인치어기뱀장어를 60 L 사각수조에각실험구별 30마리씩 3반복으로무작위배치하여 8주간사육실험을진행하였다. 각실험수조는순환여과식으로유수량은 3~4 L/min으로조절하였고, 에어레이션을통해충분한산소를공급하였으며, 평균수온은 25±1 o C를유지하였다. 일일사료공급량은전실험기간동안 1일 2회어체중의 3~4% (10:00, 18:00) 로공급하였고, 사료공급 30~60분후남은사료는수거하여 -20 o C에서보관하였다. 실험사료및실험설계실험에사용된실험사료의조성표와일반성분은 Table 1에나타내었다. 실험사료의단백질원으로어분과카제인을사용하였고, 지질원으로는어유와대두유를사용하였으며, 탄수화물원으로는전분과덱스트린을사용하여조단백질 54.5%, 조지방 15% 및가용에너지 18.2 kj/g로조절하였다. 사료내첨가물질로이용한맥반석 (Quartz porphyry, QP; Song-Gang stone, Davistone, Korea) 의조성은 Table 1에나타내었다. 실험실에서제작한사료섭취촉진물질 (BAISM, BS; patent registered, Korea) 은산가수분해물질, L-형아미노산, 핵산관련물질및염기성관련 Table 1. Composition and proximate analysis of the six experimental diets Diets (% of dry matter basis) Q 0B 0 Q 0.7B 0 Q 0.7B 0.3 Q 0.7B 0.5 Q 0.7B 0.75 Q 0.7B 1.0 Ingredients Fish meal 1 59.0 59.0 59.0 59.0 59.0 59.0 Casein 2 8.0 8.0 8.0 8.0 8.0 8.0 α-starch 3 15.0 15.0 15.0 15.0 15.0 15.0 Dextrin 4 5.0 5.0 5.0 5.0 5.0 5.0 Fish oil 5 3.0 3.0 3.0 3.0 3.0 3.0 Soybean oil 6 6.0 6.0 6.0 6.0 6.0 6.0 Quartz porphyry 7 0.0 0.7 0.7 0.7 0.7 0.7 BAISM 0.0 0.0 0.3 0.5 0.75 1.0 Cellulose 8 1.7 1.0 0.7 0.5 0.25 0.0 Other ingredients 9 4.0 4.0 4.0 4.0 4.0 4.0 Proximate analysis Crude protein 50.5 51.2 50.3 50.6 49.7 50.5 Crude lipid 15.5 14.7 14.2 15.9 15.2 14.8 Crude ash 12.2 11.8 12.0 11.9 12.4 12.2 Provided by Su-hyup Feed Co., Uiryeong, Korea. 1,3 United States Biochemical (USB), Cleveland, Ohio. 2,4,8 5 Ewa fat industry Co. Ltd., Busan, Korea. 6Dong Suh Oil & Fats, Changwon, Korea. 7Main containing minerals (% in Song-Gang stone): Ca 0.6; K 0.19; Na 0.071; Mg 0.02; Fe 0.28; Zn 0.001; P 0.01. Provided by Davistone Co., Busan, Korea. 9Other ingredients: 2% vitamin pre-mixture, 2% mineral premix (Bae et al., 2004).
28 배준영, 한경민, 이준호, 김상은, 이정열, 배승철 Table 2. The composition of feed stimulants, BAISM Composition (%) KH < 30 1 IMP < 20 2 L-type AA mixture < 20 3 Betaine < 15 3 1 Hydrolysates after removing pigments and metals with resin. 2Inosine-5'-monophosphate, Dae-sang, Co., Seoul, Korea. 3Amino acids: proline; threonine; methionine, Sigma Chemical, USA. 물질을혼합한조성물로혼합비는이전의연구 (Choi et al., 2002; Kim et al., 2002a; Han, 2003; Yoo et al., 2007) 를참고로하였고, Table 2에나타내었다. 상기두가지물질의단독및혼합첨가가치어기뱀장어에미치는영향을확인하고자기초사료에 0% QP+0% BS (Q 0B 0), 0.7% QP+0% BS (Q 0.7B 0), 0.7% QP+0.3% BS (Q 0.7B 0.3), 0.7% QP+0.5% BS (Q 0.7B 0.5), 0.7% QP+0.75% BS (Q 0.7B 0.75), 0.7% QP+1.0% BS (Q 0.7B 1.0) 의 6가지수준으로설정하여수준별로첨가하였다. 모든실험사료는원료를혼합하여펠렛기로압출성형하여제조하였고 (diameter 1 mm), 자연건조시킨다음밀봉하여 -20 o C에서보관하면서실험어에공급하였다. 어체측정및성분분석 8주간의사육실험종료후, 어체측정을위해실험어를 24시간절식시킨후 ehylene glycol phenyl ether 90% (200 ppm) 로마취시켜수준별실험어의전체무게를측정하였고, 이를통해증체율 (weight gain, WG), 사료효율 (feed efficiency, FE), 일간성장률 (specific growth rate, SGR), 단백질전환효율 (protein efficiency ratio, PER) 및생존율을조사하였다. 일반성분은실 험사료와전어체에대해서실시하였고, 전어체분석을위해서수조별로 10마리씩무작위로추출하여분쇄한전어체를사용하였다. AOAC (1995) 에의해수분은상압가열건조법 (125 o C, 3시간 ), 조단백질은 Kjeldahl 질소정량법 (N 6.25) 그리고조회분은직접회화법으로각각분석하였다. 또한, 조지방은샘플을 12시간동결건조한후 Soxtec system 1046 (Tacator AB, Sweden) 을사용하여 Soxhlet 추출법으로분석하였다. 누적생존율조사 Edwardsiella tarda 복강주사에의한누적생존율조사는 Choi et al. (2004) 의방법에따라 8주동안의사육실험종료후 24 시간동안안정화후, 어류에독성을미치는 E. tarda 부유액 (1 10 6 cfu/ml) 을 1.5% NaCl이첨가된 trypticase soy agar (TSA) 에 27 o C에서 48시간배양하여준비하였다. 60 L 사각수조에실험구별각 10마리씩 2반복으로배치하였고, 부유물을실험어의복강에주사 (0.1 ml/fish) 후일별폐사량을기록하였다. 통계처리통계처리는 SPSS program (ver. 10) 을사용하여분산분석 (one way-anova test) 을실시하여 Duncan s new multiple range test에의해평균간의유의성 (P<0.05) 을검정하였다. 결과맥반석과 BAISM의첨가수준별 6가지실험사료를 8주간섭취한치어기뱀장어의증체율, 사료효율, 일간성장률, 단백질전환효율및생존율에대한결과는 Table 3에나타내었다. 증체 Table 3. Growth performance, survival and whole body proximate composition of juvenile eel, Anguilla japonica fed six different experimental diets for 8 weeks 1 Diets 2 Pooled Q 0B 0 Q 0.7B 0 Q 0.7B 0.3 Q 0.7B 0.5 Q 0.7B 0.75 Q 0.7B 1.0 SEM 7 Growth performance Initial wt. (g) 14.9 15.2 15.1 15.2 14.9 14.8 0.07 Final wt. (g) 23.2 25.0 24.9 25.6 25.7 25.8 0.28 WG (%) 3 56.2 c 64.0 b 65.3 b 68.7 ab 72.5 a 74.8 a 1.64 FER (%) 4 39.0 c 44.5 bc 45.3 bc 47.7 ab 50.4 ab 52.0 a 1.14 SGR (%) 5 0.80 c 0.88 b 0.90 b 0.93 ab 0.97 a 1.00 a 0.02 PER (%) 6 0.71 c 0.81 bc 0.82 bc 0.87 ab 0.92 ab 0.95 a 0.02 Survival (%) 100 100 100 100 100 100 0.00 Whole body proximate composition (% of as-is basis) Moisture 68.1 67.8 67.5 67.4 67.7 67.9 0.12 Crude protein 12.7 b 13.2 b 14.8 a 15.4 a 15.7 a 16.2 a 0.41 Crude lipid 16.4 a 16.2 a 14.7 b 14.5 b 14.2 bc 13.4 c 0.33 Crude ash 2.82 a 2.76 ab 2.52 bc 2.43 c 2.32 c 2.29 c 0.07 1Values are means of triplicate groups, values in the same row not sharing a common superscript are significantly different (P<0.05). 2 Refer to Table 1. 3Weight gain: [(final body weight - initial body weight) / initial weight] 100. 4Feed efficiency ratio: (wet weight gain / dry feed intake) 100. 5 Specific growth rate: [(ln(final weight - initial weight) / days of the experiment] 100. 6Protein efficiency ratio: (body weight gain / protein intake) 100. 7Pooled standard error of mean: SD/ n.
뱀장어사료내맥반석과 BAISM 혼합첨가효과 29 율과일간성장율에있어서맥반석단독첨가구 (Q 0.7B 0) 와맥반석BAISM 복합첨가구 (Q 0.7B 0.3, Q 0.7B 0.5, Q 0.7B 0.75, Q 0.7B 1.0) 는대조구 (Q 0B 0) 에비하여유의하게높았다 (P<0.05). 특히, 맥반석 BAISM 복합첨가구들중 BAISM 0.5% 이상의실험구 (Q 0.7B 0.5, Q 0.7B 0.75, Q 0.7B 1.0) 는나머지실험구들 (Q 0B 0, Q 0.7B 0, Q 0.7B 0.3) 에비해유의하게높았고 (P<0.05), 세가지수준에대한유의한차이는없었다 (P>0.05). 사료효율과단백질전환효율에있어서맥반석 BAISM 복합첨가구들중 BAISM 0.5% 이상의실험구 (Q 0.7B 0.5, Q 0.7B 0.75, Q 0.7B 1.0) 는 BAISM 0.3%(Q 0.7B 0.3) 첨가구와맥반석단독첨가구 (Q 0.7B 0) 및대조구 (Q 0B 0) 에비해유의하게높았고 (P<0.05), 세가지수준에대한유의한차이는없었다 (P>0.05). 한편, 본실험에서는 8주간의성장실험기간모든실험구의생존율은 100% 로사료내맥반석과 BAISM의단독혹은복합첨가에대한유의한영향은없는것으로나타났다. 8주간의수준별 6가지실험사료를섭취한치어기뱀장어에대한전어체의일반성분분석결과는 Table 3에나타내었다. 전어체의단백질함량은맥반석BAISM과복합첨가구 (Q 0.7B 0.3, Q 0.7B 0.5, Q 0.7B 0.75, Q 0.7B 1.0) 가맥반석단독첨가구 (Q 0.7B 0) 와대조구 (Q 0B 0) 에비해유의하게높은반면 (P<0.05), 복합첨가구간에는유의한차이가없었다 (P>0.05). 지질함량은 BAISM 0.75% 이상첨가구인 Q 0.7B 0.75, Q 0.7B 1.0 실험구가나머지실험구들에비해유의하게높았으나, Q 0.7B 0.75, Q 0.7B 1.0 실험구간에는유의한차이가없었다 (P>0.05). 회분함량은 Q 0B 0 와 Q 0.7B 0 가나머지실험구들에비해유의하게높았으나 (P<0.05), Q 0B 0 와 Q 0.7B 0 간에는유의한차이가없었다 (P>0.05). 한편, 전어체의수분함 Fig. 1. Cumulative survival rate after intraperitoneal injection with Edwardsiella tarda in six experimental group of juvenile eel, Anguilla japonica. Diets: Control group (Q 0B 0), 0.7% QP+0% BS (Q 0.7B 0), 0.7% QP+0.3% BS (Q 0.7B 0.3), 0.7% QP+0.5% BS (Q 0.7B 0.5), 0.7% QP+0.75% BS (Q 0.7B 0.75), or 0.7% QP+1.0% BS (Q 0.7B 1.0), respectively. Date were mean of triplicate tanks of 10 fish. Asterisk and different letters in the squares indicates a significant (P<0.05) difference by Duncan s new multiple range test. See legend in Table. 1 for further details.
30 배준영, 한경민, 이준호, 김상은, 이정열, 배승철 량은 67.4~68.1% 로모든실험구에서유의한차이가없었다 (P>0.05). Edwardsiella tarda FPC 799 균주로복강내주사후각실험구별누적생존율을조사한공격실험의결과는 Fig. 1에나타내었다. 그결과, 대조구에서는복강주사 4일후부터폐사개체가나타나기시작하였고, 누적생존율은주사 5일후부터맥반석BAISM 단독혹은복합첨가구에비해유의하게낮은것으로나타났으며 (P<0.05), 7~8일전후로폐사량이급증하여주사 9일후에모든실험어가폐사하였다. 맥반석단독혹은 BAISM 복합첨가구에서는균주투여 7일전후로폐사개체가발생하기시작하여 10~12일전후로폐사율이급증하였다. 주사 15일후, 맥반석단독첨가구 (Q 0.7B 0) 와 BAISM 0.5% 이상첨가구 (Q 0.7B 0.5, Q 0.7B 0.75, Q 0.7B 1.0) 의누적생존율은 Q 0.7B 0.3 실험구에비해유의하게높게나타났으나 (P<0.05), 이들실험구간에는유의한차이가없었으며 (P>0.05), 전실험구에서 40% 이상의누적생존율을나타내었다. 고 이연구는사료내맥반석 (quartz porphyry) 과 BAISM의효과를확인하고자치어기뱀장어의사료내 6가지수준별로맥반석단독혹은 BAISM 복합첨가한사료를 8주간공급한결과성장과체조성에영향을미치는것으로나타났고, 성장실험이후공격실험을통해내병성증대에도효과가있는것으로확인되었다. Choi et al. (2004) 는치어기넙치에맥반석을사료내 0.5~2.0% 첨가시성장률과사료효율증대와는직접적인관련성이없는반면 0.5% 첨가시질병저항성및항균제로서효과가있다고보고하였다. 한편, 가축과가금의사료에소량첨가하여공급하면증체량, 산란율및사료효율이개선되고 (Kumich and Reid, 1960; Almquist et al., 1967), 육계사료내맥반석첨가시배설물의수분함량감소및영양소를효율적으로이용할수있는것으로보고되었으며 (Son and Park, 1997), 맥반석을이용한유기농법의개발과축산에서소화개선등의사료내이용가능성에대한연구들이지속적으로이루어지고있다 (Choi et al., 1987; Son et al., 1998). 맥반석은화성암류중석영암반에속하는암석으로 SiO 2 와 Al 2CO 3 및 40여종의미네랄로구성되어있고, 생체발육과생리기능을조절하여세포의활력을유지한다. 이로인해동식물의각종질병예방과치료, 살균작용, 체내해독, 교감신경계의억제작용, 생육촉진, 수확량증가의효과가있는것으로알려져있다 (Hayashi, 1997). 이러한미네랄 (Fe, Cu, Mn, Zn 등 ) 은제한적으로사용되고, 효소반응과 non-enzymatic macromolecules의구성요소로작용한다 (Watanabe et al., 1997). 이연구에서사료내맥반석 0.7% 첨가시대조구에비해성장과사료효율이유의하게높았다. 이는규산염광물질인맥반석은그결합력이약하기때문에뱀 찰 장어의체내에서유리되어효율적으로이용되었을것으로판단되며, 향후맥반석의어떠한성분이성장증대에기여를하는지체내생화학적인반응을확인할수있는연구가수행되어야할것이다. 어류에있어섭취촉진물질은분자량이 1,000 미만의수용성물질로대부분아미노산, 핵산관련화합물, 유기산및당류등이이에속하며, 초기유생의입붙임용사료나식물성단백질원사료의기호성증대를위해주로이용되고있다. 이연구에서사료섭취촉진물질로이용한 BAISM은실험실에서제작한산가수분해물질 (KH), L-형아미노산복합물, 핵산관련물질 (IMP), 그리고염기성관련물질 (betaine) 을혼합한조성물로여러어종에서그효과가보고된바있다 (Choi et al., 2002; Kim et al., 2002a; Han, 2003; Park, 2004; Yoo et al., 2007). BAISM의주요성분인 KH는단백질을가수분해하여분리가능한아미노산을회수한후, 다량의아미노산을포함하고있는잔여물중어류에필요한주요필수아미노산과사료섭취를촉진할수있는다양한아미노산을포함하고있어경제성있는저가의양어용배합사료의영양강화및사료섭취촉진물질로이용할수있다. 이에대해 Choi et al. (2002) 은조피볼락에있어섭취촉진효과는사료내 KH에포함된여러가지아미노산들의혼합상승효과에기인한것으로보고하였고, Harada et al., (1987) 은전복, 미꾸라지및방어의섭취촉진효과는이러한화합물의혼합에의해상승한다고보고하였다. 자연계에서일반적으로존재하는 L-형아미노산은 Anguilla anguilla (Mackie and Mitchell, 1983), A. japonica (Takeda et al., 1984), Salmo gairdneri (Adron and Mackie, 1978) 의섭취촉진에효과가있는것으로보고되었다. 또한, L-형아미노산복합물의상승효과에관해서 A. japonica는 Alanine, Glycine, Proline, Histidine (Takii et al., 1986), A. anguilla는 Glutamine, Asparagine, Glutamic acid, Alanine (Sola and Tongiorgi, 1998) 이섭취촉진효과가있는것으로알려져있다. 상기연구들에이용된 L-형아미노산과본실험에서이용된 L-형아미노산 (Proline, Threonine, Methionine) 은약간의차이를보이고있지만, 섭취촉진효과는인정되었다. 이에대해향후뱀장어에적합한아미노산들의검증을통해효과적인사료섭취촉진물질개발에관한연구가다각적으로수반되어야할것으로판단된다. 핵산관련물질인 IMP와염기성관련물질인 betain은단독첨가효과보다는아미노산과복합첨가에의한혼합상승효과에의해대상어류의사료섭취효과를증대시키는것으로알려져있다 (Carr et al., 1977; Ikeda et al., 1988). 본연구결과치어기뱀장어사료내맥반석 0.7% 를단독첨가하여공급한실험구가대조구에비해성장률과사료효율이유의하게높았고, 여기에 BAISM 0.5% 이상을복합첨가한실험구가다른실험구들에비해유의하게높은것으로보아맥반석과 BAISM이치어기뱀장어에사료섭취촉진효과에의한감각자극들이소화흡수및영양소의대사를활성화하여성장과
뱀장어사료내맥반석과 BAISM 혼합첨가효과 31 사료효율이향상된것으로판단된다. 이러한물질들에대한혼합상승효과는 Micropterus salmoides과 Morone saxatilis에서성장률과사료효율을향상시킨다는다른어종에서의보고와도일치하였다 (Kubitza et al., 1997; Papatryphon and Soares, 2001). 향후, 상기에이용된첨가제들에대한이러한생리적작용및생리기구에대한연구가수반되어야할것이다. 성장실험종료후각실험구에대한전어체성분의분석결과맥반석과 BAISM의첨가수준별수분의함량에는모든실험구에서유의한차이가없었고 (P>0.05), 단백질함량은첨가수준에따라유의적으로증가한반면 (P<0.05), 지질과회분의함량은유의적으로감소하는경향을나타내었다 (P<0.05). Cyprinus carpio에서성장이빠른실험구의경우, 전어체의단백질과회분은함량변화가적으나지질함량은증가한다고보고하였고 (Murai et al., 1985), Plecoglossus altivelis에서체내축적된지방은지방대사의호르몬조절작용에의해단백질로전환되거나에너지로이용되는것으로보고되었다 (Nematipour et al., 1990). 또한, Paralichthys olivaceus에서성장률과사료효율이높은실험구일수록단백질함량은증가하는반면, 지방함량은감소하는경향을나타내었다 (Kim et al., 2002b). 본실험의경우성장률이높은실험구에서지방함량이낮은것은이전의연구결과와같이성장의촉진으로인한대사량증가로에너지요구가증가함에따라지방이소비된결과로이는전어체내단백질의축적률증가와지방대사의활성화를통한지방축적을감소시켜건강한상태를유지하고고급육질생산에도기여할것으로판단된다. 8주간의성장실험기간동안사료내맥반석과 BAISM 첨가수준에관계없이생존율은모두 100% 로유의한차이가없었다. 이후, 맥반석과 BAISM의단독혹은복합첨가에따른수준별실험사료를섭취한실험어들의내병성및항균력을확인하고자실시한공격실험에서맥반석과 BAISM의단독혹은복합첨가첨가구가대조구에비해유의하게낮은초기폐사율을나타내었다. 특히, BAISM 0.5% 이상복합첨가구가공격실험에서좋은효과가있는것으로확인되었다. 이러한결과로볼때, 8주동안의성장실험기간동안체내에맥반석과 BAISM 의축적효과가나타난것으로판단된다. 이러한결과는타어종에서치어기넙치사료내 aloe 0.5% (Kim et al., 2002c), songgang stone 0.5% (Choi et al., 2004) β-1,3 glucan 0.1%+BAISM 0.9% (Yoo et al., 2007) 첨가시, E. tarda에대한내병성이있는것으로보고된결과를뒷받침할수있다. 따라서이연구의결과에의하면치어기뱀장어에있어사료첨가제로써맥반석 0.7% 와 BAISM 0.5% 를첨가하는것이성장, 사료효율, 내병성증대및육질개선에좋은효과가있을것으로판단된다. 이를통해뱀장어양식과같은고밀도사육환경에서빈번한어병발생으로인한생산성저하와항생제남용과같은당면한문제에대한하나의방편이될수있을것으로기대한다. 요 이연구는치어기뱀장어 Anguilla japonica의사료내맥반석 (quartz porphyry, QP) 과 BAISM을단독및혼합첨가가성장과내병성에미치는영향을확인하고첨가제로써이용성을평가하였다. 사료내첨가물질로맥반석 (Quartz porphyry, QP) 과실험실에서제작한섭취촉진물질인 BAISM (BS) 을기초사료에각각 0% QP+0% BS (Q 0B 0), 0.7% QP+0% BS (Q 0.7B 0), 0.7% QP+0.3% BS (Q 0.7B 0.3), 0.7% QP+0.5% BS (Q 0.7B 0.5), 0.7% QP+0.75% BS (Q 0.7B 0.75), 0.7% QP+1.0% BS (Q 0.7B 1.0) 의 6가지수준으로첨가하였다. 실험어는 4주간예비사육후, 평균어체중 15±0.3 g (mean±sd) 인치어기뱀장어를 60 L 사각수조에실험구별 30 마리씩 3반복으로무작위배치하여 8주간사육실험을진행하였다. 사육실험종료후, Edwardsiella tarda 복강주사에의한누적생존율을조사하였다. 증체율, 일간성장률, 사료효율, 단백질전환효율에서맥반석단독첨가구 (Q 0.7B 0) 와맥반석 BAISM 복합첨가구 (Q 0.7B 0.3, Q 0.7B 0.5, Q 0.7B 0.75, Q 0.7B 1.0) 는대조구 (Q 0B 0) 에비하여유의하게높았다 (P<0.05). 특히, 맥반석 BAISM 복합첨가구들중 BAISM 0.5% 이상의실험구 (Q 0.7B 0.5, Q 0.7B 0.75, Q 0.7B 1.0) 는나머지실험구들에비해유의하게높았고 (P<0.05), 이들에대한유의한차이는없었다 (P>0.05). 전어체일반성분의분석결과수분함량은전실험구에서유의한차이가없었고 (P>0.05), 단백질함량은첨가수준에따라유의적으로증가한반면 (P<0.05), 지질과회분의함량은유의적으로감소하는경향을나타내었다 (P<0.05). E. tarda에의한공격실험결과주사 15일후, 맥반석 BAISM 0.5% 이상혼합첨가구의누적생존율은다른실험구에비해유의하게높았고 (P<0.05), 전실험구에서 40% 이상의누적생존율을나타내었다. 따라서치어기뱀장어사료에맥반석 0.7% 와 BAISM 0.5% 를첨가하는것이성장과사료효율증대및질병저항성증진에효과가있을것으로판단된다. 사 본연구는 2004년도부경대학교기성회학술연구비지원과제에의하여수행된결과이며, 본과제의산학협동후원사인 ( 주 ) 다비스톤에감사드립니다. 약 사 참고문헌 Adron, J. W. and A. M. Mackie, 1978. Studies on the chemical nature of feeding stimulants for rainbow trout, Salmo gairdneri Richardson. J. Fish Biol., 12, 303 310. Almquist, H. J., H. L. Christensen and J. Maurer, 1967. The effect of bantonites on nutrient retention by turkeys. Feedstuffs, 39, 54 56.
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뱀장어사료내맥반석과 BAISM 혼합첨가효과 33 Wendelaar Bonga, S. E., 1977. The stress response in fish. Physiol. Rev., 77, 591-625. Yoo, S. J. 2003. Removal characteristic of heavy metal by Song- Gang stone. MS thesis, Kyungsung University, Busan, Korea, 65 pp. Yoo, G. Y., S. H. Lee, Y. C. Kim and O. E. Okorie, 2007. Effects of dietary β-1,3 glucan and feed stimulants in juvenile olive flounder, Paralichthys olivaceus. J. World Aquacult. Soc., 38(1), 138 145. 원고접수 :2008 년 1 월 10 일수정본수리 : 2008 년 2 월 18 일